Crank-arm.



B. B. CRAFT.

CRANK ARM.

APPLICATION rILnn JULY 14, 1009.

1,079,472. Patented Nov. 25, 1913.

Fig.

UNITED sTATEs PAT NT orrion.

EDWARD B. CRAFT, OF HACKENSACK, NEW JERSEY, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, OF NEW YORK. N. Y., A CORPORATION OF ILLINOIS.

CRANK-ARM.

Specification of Letters Patent.

Patented Nov. 25, 1913.

Application filed. July 14, 1909. Serial No. 507,492.

To all who-m 'Ztmay concern.

Be it known that I, Eowano B. CRAFT, citizen of the United States, residing at l-Iackensack, in the county of Bergen and State of New Jersey, have invented a certain new and useful Improvement in Crank- Arms, of which the following is a full, clear, concise, and exact description.

This invention relates to cranks for use with magneto generators or like mechanism and has for its object the provision of a crank, which will be neat in appearance, strong, durable and cheap to manufacture. Heretofore the cranks used in connection with such mechanism have usually been made of two pieces of metal, one piece-being a sleeve for engaging the generator shaft which piece is formed of drawn metal and the other piece, a crank arm, being formed of a stamping and secured to the sleeve by riveting or some other like method. Such a structure necessitates extra labor both in forming and assembling the parts thereof. Moreover, in a crank thus formed or" two parts and secured together in a right angle relation to each other it frequently happens that the arm becomes loosened from the sleeve thus rendering the generator inoperative and useless when it is desired to ring. 7

According to this invention the crank is an integral structure formed of a single strip of sheet metal and punched and turned into its final shape which comprises a tubular sleeve and an integral arm bent at right angles thereto, the lateral edges of said arm being turned inwardly to form stiffening ridges and the extremity of the arm fiattencd to support a handle. A crank thus formed is strong and durable owing to the absence of riveted parts and it is also one which can be produced at a cost much less than the two piece crank.

Figure 1 is a view in elevation of the crank applied to a manually-operated magneto-generator; Fig. 2 is a perspective view of the/crank; Fig. {3 is a front view; Fig. 4 is a view of a blank of sheet metal from which the crank is formed; Fi 5 is a side View showing the crank in process of being formed; Fig. 6 is an end view of the same; and Fig. 7 is a longitudinal section of the completed crank.

The blank 1 may be stamped out from a sheet of brass, preferably in the form shown in Fig. 4, with projections 22, 2 and a tapen ing body 3 terminating in a rounded end 4. The blank is then curved laterally for substantially its entire length and bent longitudinally in substantially a right angle, (but with a rounded corner) being then in the form shown in Figs. 5 and (i, with the projections 2, 2 outstanding. These projections are then brought together to "form a tubular sleeve 5 which may be int-criorly threaded as shown at 6 for-attachment to the generator crank shaft, 8. The laterally-curved portion 7 forms the crank arm, and the upstanding portions or ribs 9, 10 thereof strengthen the same and give it the necessary rigidity. At. this stage, the crank may be given a plating of nickel, or otherwise finished.

As is evident by reference to Figs. 5 and 6, the end portion a is left fiat to provide a bearing surface for an insulating handle 11.

.The said handle may be rotatably mounted upon a pin 12, which is threaded in the opening 13 and then upset, so as to be held tightly in place. The said opening is preferably punch d in the blank at the time the blank is stai'np-cd out.

Having thus described my invention, 1

claim as new and desire to secure. by Letters Patent of the United States the following l. A crank, formed from a blank of sheet metal having a rectangular end from which the sides of the blank converge to the other end, comprising an intcriorly threaded cylindrical sleeve portion formed from said rectangular end, an arm portion at right angles to the slccv'e portion and formed from the remainder of the blank, the edges of which are turned in at right angles to the body of said arm portion, a ilat end portion, and a handle pivotally mounted upon said end portion.

2; A generator crank formed from a sheet metal blank, comprising a cylindrical 'intemy name this thirteenth day of July A. 1)., riorly threaded sleeve portion, a trough 1909. shaped crank arm at right angles thereto, said crank arm having a flattened end por- 5 ti'gn, and a handle pi'votally mounted upon lVitnesses:

said end portion. IRVING MACDONALD, In witness whereof, I hereunto subscribe RALPH Jornmsmi.

EDWARD B. CRAFT. 

